Lubricity measurement using MEMs sensor

ABSTRACT

A system that facilitates in situ determination of lubricity in a fluid comprises a multi-element sensor positioned within a machine, wherein the multi-element sensor obtains data regarding a plurality of parameters of a fluid. A component calculates lubricity of the fluid based at least in part upon the measured parameters.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.11/297,267, filed Dec. 8, 2005, now U.S. Pat. No. 7,228,727, andentitled LUBRICITY MEASUREMENT USING MEMS SENSOR, which is a Divisionalof U.S. patent application Ser. No. 10/675,846, filed Sep. 30, 2003, nowU.S. Pat. No. 7,024,920, and entitled LUBRICITY MEASUREMENT USING MEMSSENSOR, the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention generally relates to measurement and analysis ofmultiple parameters of fluids utilized in machinery. More particularly,the invention relates to a system and/or methodology that facilitatescontinuous in situ measurement and analysis of lubricity of a fluid.

BACKGROUND OF THE INVENTION

Dynamoelectric machines, such as motors and generators and otherrotating machines, such as gears and bearing systems, are widelyemployed in industrial and commercial facilities. These machines arerelied upon to operate with minimal attention and provide for long,reliable operation. Many facilities operate several hundred or eventhousands of such machines concurrently, several of which are integratedinto a large interdependent process or system. Like most machinery, atleast a small percentage of such equipment is prone to failure. Some ofthese failures can be attributed to loss of lubrication, incorrectlubrication, lubrication breakdown, or lubrication contamination.

Depending on the application, failure of a machine in service canpossibly lead to system or process latency, inconvenience, materialscrap, machinery damage, hazardous material cleanup, and even adangerous situation. Thus, it is desirable to diagnose machinery forpossible failure or faults early in order to take preventive action andavoid such problems. Absent special monitoring for certain lubricationproblems, a problem may have an insidious effect in that although only aminor problem on the outset, the problem could become serious if notdetected. For example, bearing problems due to inadequate lubrication,lubrication contamination or other causes may not become apparent untilsignificant damage has occurred.

Proper lubrication facilitates extension of machinery life. For example,when motor lubricant is continuously exposed to high temperatures, highspeeds, stress or loads, and an oxidizing environment, the lubricantwill deteriorate and lose its lubricating effectiveness. The loss oflubricating effectiveness will affect two main functions of alubrication system, namely: (1) to reduce friction; and (2) to removeheat. Continued operation of such a degraded system may result in evengreater heat generation and accelerated system degradation eventuallyleading to substantial machinery damage and ultimately catastrophicfailure. To protect the motor, the lubricant should be changed in atimely fashion. However, a balance must be struck—on one hand it isundesirable to replace an adequate lubricant but on the other hand it isdesired to replace a lubricant that is in its initial stages ofbreakdown or contamination prior to occurrence of equipment damage. Aseach particular application of a lubricant is relatively unique withrespect to when the lubricant will breakdown or possibly becomecontaminated, it becomes necessary to monitor the lubricant.

Lubricity can be defined as “an ability of a lubricant to reducefriction between moving, loaded surfaces.” Prior to a mandated reductionin the sulfur content of diesel fuels in the early 90's, no acceptablemeasurement of lubricity of a fluid was defined. Reduction of sulfur indiesel fuels typically is accomplished via hydro heating, whichinadvertently removes lubricating elements from the fuels. Suchreduction of sulfur (and thus lubricating elements) has caused prematureequipment breakdowns and, in some cases, catastrophic failure. Thus, ademand arose for a system and/or methodology for testing for lubricityof a fluid. Laboratory procedures and measures of lubricity were definedand incorporated into ASTM standards. Such procedures include theStandard Test Method for Evaluating Lubricity of Diesel Fuels by theScuffing Load Ball-on-Cylinder Lubricity Evaluator (SLBOCLE), the TestMethod for Evaluating Diesel Fuel Lubricity by an Injection Pump Rig,the Standard Test Method for Evaluating Lubricity of Diesel Fuels by theHigh-Frequency Reciprocating Rig (HFRR), and other laboratory testingprocedures.

Unfortunately, performing the testing methods described above requiresexpensive, bulky equipment. Furthermore, the ASTM testing methodsrequire a substantial amount of time for completion, and moreoverrequire operator intervention. More importantly, these tests must bedone off-line in a laboratory or bench-top setting. They cannot be doneon-line, in real time as the machinery operates. It is to be understood,however, that no standard of lubricity presently exists—only disparateprocedures for testing lubricity. The measurements obtained viaemploying the ASTM testing methods are error-prone due to complexity ofsuch testing procedures, and reproducing the measurements forverification purposes is difficult due to an amount of time required forobtaining a measurement. Moreover, the laboratory testing procedures donot account for an environment in which a lubricant will be employed.For instance, surface coating of metallic parts within a machine canimpact an ability of a lubricant to effectively mitigate wear betweentwo moving components. Also, a fluid's ability to carry particularparticles within an operating environment can impact lubricity of thefluid. With a continuing trend towards limiting the amount of sulfurpresent in fuels and lubricants, an in situ sensor that continuouslymonitors lubricity of a fluid can mitigate breakdown and catastrophicfailure of machinery.

In view of at least the above, there exists a strong need in the art fora system and/or methodology facilitating continuous in situ measurementand analysis of parameters relating to fluid lubricity, and a systemand/or methodology for maintaining such fluids.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an extensive overview of the invention. It is intended toneither identify key or critical elements of the invention nor delineatethe scope of the invention. Its sole purpose is to present some conceptsof the invention in a simplified form as a prelude to the more detaileddescription that is presented later.

The present invention facilitates in situ attainment of a measurement oflubricity of a fluid as well as attainment of a Fourier Transform InfraRed spectrum plot. The present invention is a significant improvementover conventional systems and/or methods for determining lubricity of afluid in that an inexpensive multi-element sensor can be employed toobtain data necessary to calculate lubricity. Moreover, themulti-element sensor can be extremely small, thereby allowing placementof the sensor in positions within machinery that lubricity is extremelyimportant to proper operation of the machinery (e.g., fuel pumps,bearing raceways, . . . ). Furthermore, the present inventionfacilitates continuous monitoring of various parameters of a fluid, andthus facilitates continuous monitoring of lubricity, as lubricity iscalculated based at least in part upon data obtained from themulti-element sensor. After a measurement relating to automaticallymaintaining fluid as well as automatically controlling operation of amachine. For example, if fluid displays insufficient lubricity,additives that enhance lubricity can be added to the fluid. Moreover,the speed of operation of a machine can be accelerated or slowed basedupon obtained values of lubricity.

Multi-elements sensor(s) are employed to obtain data regarding aplurality of parameters of a fluid utilized in machinery. Suchparameters can include but are not limited to temperature, pH,viscosity, density, oxidation, TAN, presence of water, presence of ZDDPand/or TCP, conductance, etc. The data can thereafter be received by acomponent that facilitates filtering and/or fusion of such data. Thecomponent can utilize models based on laboratory test proceduresemployed to measure lubricity of various fluids. More particularly, thecomponent can include a first-order chemical model and patternrecognition algorithms that correlate sensor readings with laboratorylubricity measurements.

In accordance with one aspect of the present invention, MEMs viscositysensors can be employed in connection with determining lubricity of afluid. Finger-like elements of the viscosity sensors can be coated onsurfaces moving in close proximity with disparate surfaces. A voltagesource can cause the finger-like elements to vibrate, and upon backingout the voltage data is obtained regarding an ability of a fluid toadhere to the disparate surfaces. Such ability to adhere (or“stickiness”) is relevant to lubricity of the fluid. Furthermore, thefinger-like elements of the viscosity sensors can be disparately spaced,thereby leaving larger gaps between finger-like elements in a particularviscosity sensor compared to a differing viscosity sensor. Voltages canthen be applied to the viscosity sensors causing the finger-likeelements of the viscosity sensors to vibrate. Upon backing out thevoltage, comparative measurements pertaining to an ability of the fluidto adhere to disparately spaced finger-like elements can be employed inconnection with robustly calculating lubricity.

In accordance with another important aspect of the present invention,several non-traditional sensing elements can be provided on themulti-element sensor. For instance, two surfaces can be provided forcesthat require such two surfaces to contact one another. The forces willbe applied to require generation of a frictional force between the twosurfaces. Monitoring forces utilized to generate the frictional forceand relative displacement between the two surfaces enables additionaldata relevant to lubricity of the fluid to be obtained.

To the accomplishment of the foregoing and related ends, the inventionthen, comprises the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspects ofthe invention. These aspects are indicative, however, of but a few ofthe various ways in which the principles of the invention may beemployed and the present invention is intended to include all suchaspects and their equivalents. Other objects, advantages and novelfeatures of the invention will become apparent from the followingdetailed description of the invention when considered in conjunctionwith the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system that facilitates calculation oflubricity of a fluid within machinery in accordance with an aspect ofthe present invention.

FIG. 2 is a block diagram of a system that facilitates automaticmaintenance of a fluid and automatic control of machinery based upon acalculation of lubricity in accordance with an aspect of the presentinvention.

FIG. 3 is a block diagram of a system that facilitates calculation oflubricity of a fluid within machinery in accordance with an aspect ofthe present invention

FIG. 4 illustrates a methodology for calculating lubricity in accordancewith an aspect of the present invention.

FIG. 5 illustrates a methodology for automatically maintaining a fluidbased at least in part upon a calculated lubricity measurement inaccordance with an aspect of the present invention.

FIG. 6 is an exemplary multi-element sensor that can be utilized inconnection with the present invention.

FIG. 7 is an exemplary multi-element sensor that can be utilized inconnection with the present invention.

FIG. 8 is an exemplary multi-element sensor that can be utilized inconnection with the present invention.

FIG. 9 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 10 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 11 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 12 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 13 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 14 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 15 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 16 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 17 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 18 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 19 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 20 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 21 is an exemplary sensing element that can be utilized to obtaindata relevant to lubricity of a fluid in accordance with one aspect ofthe present invention.

FIG. 22 is an illustrative flow diagram illustrating a methodology forcalculating lubricity of a fluid in accordance with one aspect of thepresent invention.

FIG. 23 is an exemplary Fourier Transform Infra Red spectrum plot inaccordance with an aspect of the present invention.

FIG. 24 is an exemplary Fourier Transform Infra Red spectrum plot inaccordance with an aspect of the present invention.

FIG. 25 is an exemplary environment in which the present invention canbe employed.

FIG. 26 is an exemplary schematic in accordance with one aspect of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the present invention. It may be evident, however, thatthe present invention may be practiced without these specific details.In other instances, well-known structures and devices are shown in blockdiagram form in order to facilitate describing the present invention.

As used in this application, the term “computer component” is intendedto refer to a computer-related entity, either hardware, a combination ofhardware and software, software, or software in execution. For example,a computer component may be, but is not limited to being, a processrunning on a processor, a processor, an object, an executable, a threadof execution, a program, and/or a computer. By way of illustration, bothan application running on a server and the server can be a computercomponent. One or more computer components may reside within a processand/or thread of execution and a component may be localized on onecomputer and/or distributed between two or more computers.

Referring now to the drawings, FIG. 1 illustrates a high-level systemoverview in connection with one particular aspect of the subjectinvention. The present invention relates to a novel system 100 forproviding continuous in situ indications of lubricity of a fluid withinmachinery. A model of lubricity can be generated based upon ASTMprocedures. For example, the present inventor analyzed variousmeasurements obtained from disparate ASTM tests to provide a robustmodel of lubricity. The present invention utilizes various parametersthat, while not directly measuring lubricity, can indicate lubricity ofa fluid in a machine. Furthermore, the parameters can be continuouslysensed in situ with sensing components that are much less expensive thanequipment required under ASTM standards. The sensing components are alsosmaller, lighter, operate automatically, operate continuously, operaterepeatedly, and require less power than equipment required under ASTMstandards. Parameters obtained from the sensing components canthereafter be employed to maintain fluid to contain sufficient lubricitygiven a particular application. Substantially similar parameters canfurther be utilized to generate an FTIR spectrum to further analyze thefluid.

The system 100 includes a sensor 102 that includes a plurality of sensorelements 104 employed to obtain measurements of various parameters of afluid, such as temperature, pH, viscosity, presence or particularadditives, electro-chemical activity, TAN, density, dielectric, etc.Furthermore, the sensor elements 104 can include devices specificallydesigned to determine an index of lubricity. For instance, two surfacescan be provided, wherein actuators or other force-providing devices canprovide one or more forces to create friction between the surfaces. Anamount of force provided and the relative motion between the surfacescan be one particular measurement that is indicative of lubricity. Foranother example, an amount of fluid that adheres to a vibrating surfacecan be another parameter indicative of lubricity.

The sensor 102 is immersed in a fluid 106, and the sensor elements 104can obtain measurements of parameters relating to the fluid 106 (e.g.,temperature, density, . . . ). The fluid 106 can be in a fluidreservoir, in a flow line within machinery, in a filter, in a pump, in avalve, or within other such structure, component, or material exposed toa fluid. Ideally, the sensor 104 is positioned within machinery wherefriction of moving parts can result in machine wear and/or breakdown.For instance, the sensor 104 can be positioned in a bearing raceway, afuel pump, and/or any other suitable position within machinery. Thesensor 104 can be extremely small, thereby enabling positioning of thesensor 104 within components of machinery that are typically difficultor impossible to reach by a service engineer. The small size and lowcost of the sensor 104 permits embedding multiple sensor devices in aparticular machine, enabling determination of lubricity at variouslocation(s) within a machine and in secondary fluid and alternate fluidreservoirs or fluid systems such as a reserve fuel system or secondaryhydraulic system in an aircraft. Positioning of the sensor 104 withinmachinery enables determining lubricity within an operating environment,rather than extracting a sample of the fluid 106 and performinglaboratory tests on such fluid 106. This in situ monitoring isbeneficial, as an operating environment can affect lubricity of thefluid 106. For instance, surface condition such as surface material andsurface charge field can affect lubricity of a fluid. Moreover, anability of fluid to carry chemical compounds within machinery will alsoaffect the lubricity of the fluid 106.

The parameters of the fluid 106 sensed by the sensor elements 104 canthen be received by a sensor filter/fusion component 108, whichfacilitates generation of a robust lubricity measurement 110 from aplurality of sensed parameters. The sensor filter/fusion component 108can employ neural networks, Bayesian belief networks, support vectormachines, expert systems, fuzzy logic, data fusion engines, fluid models(chemical, fluid transport, tribological, molecular-physics, andstochastic) and other “intelligent” networks or a combination of thesetechniques to utilize sensed parameters of the fluid 106 to output alubricity measurement 110. For instance, the sensor filter/fusioncomponent 108 can provide weights to parameters sensed by the sensorelements 104. In particular, the sensor filter/fusion component 108 canallow particular parameters of the fluid 106 to be of greater influencethan various other parameters in outputting the lubricity measurement110 when given that the sensor 102 is at a particular position withinmachinery and the machinery is at a specific level of operation.Moreover, the sensor filter/fusion component 108 can include a model andpattern recognition algorithms to correlate sensor readings withlaboratory lubricity measurements. One particular sensor fusion systemand/or methodology that can be employed in connection with the presentinvention is described in U.S. Pat. No. 6,286,363, entitled INTEGRATEDMULTI-ELEMENT LUBRICATION SENSOR AND HEALTH LUBRICANT ASSESSMENT SYSTEM,which as mentioned above is hereby incorporated by reference in itsentirety.

In accordance with another aspect of the present invention, the sensorfilter/fusion component 108 can infer weighting of parameters of thefluid 106 based at least partly on prior usage and current context of auser and/or machine. As used herein, the term “inference” refersgenerally to the process of reasoning about or inferring states of thesystem, environment, and/or user from a set of observations as capturedvia events and/or data. Inference can be employed to identify a specificcontext or action, or can generate a probability distribution overstates, for example. The inference can be probabilistic—that is, thecomputation of a probability distribution over states of interest basedon a consideration of data and events. Inference can also refer totechniques employed for composing higher-level events from a set ofevents and/or data. Such inference results in the construction of newevents or actions from a set of observed events and/or stored eventdata, whether or not the events are correlated in close temporalproximity, and whether the events and data come from one or severalevent and data sources. Various classification schemes and/or systems(e.g., support vector machines, neural networks, expert systems,Bayesian belief networks, fuzzy logic, case-based reasoning, beliefmodels, data fusion engines . . . ) can be employed in connection withperforming automatic and/or inferred action in connection with thesubject invention. For example, the sensor filter/fusion component 108can infer weights to be given to each fluid parameter even when amachine is not in operation based upon prior usage of the machine. Thus,prior to starting and/or restarting the machine an operator can confirmthat sufficient lubricity exists for the typical operation of themachine.

In accordance with another aspect of the present invention, thedetermined lubricity measurement can be employed to control chemicalswithin the fluid 106 before, during, and/or after machine operation. Forinstance, the lubricity measurement can be utilized to automaticallyinject components that provide greater lubricity to a fluid duringinstances that the lubricity measurement 110 isn't sufficient. Asanother example, when high fluid stress is sensed and limited lubricityis determined from sensor measurements, a prescribed amount of EP(extreme pressure) additive may be admitted to the system to establishan acceptable level of lubricity. The resultant new value of lubricityis then measured to confirm that the expected change in lubricity has infact occurred and that the sensing, control, additive reservoir, andother system components are working properly. Furthermore, the obtainedlubricity measurement can be employed to confirm that the fluid iscapable of meeting severe loads, and that fluid lifetime and machinerylifetime has been extended. Moreover, an ability to provide a continuousmeasurement of lubricity in connection with controlling lubricity of thefluid 106 ensures that catastrophic breakdown of machinery will notoccur due to lack of lubricity.

The sensor filter/fusion component 108 can also be utilized inconnection with the sensor elements 104 to synthesize a FourierTransform Infra-Red (FTIR) spectrum plot 112. Particular compounds andcontaminants in the fluid 106 that are sensed utilizing laboratorytechniques such as FTIR spectroscopy also affect sensor readings for aplurality of parameters of the fluid 106 (e.g., pH, water, TAN, chemicalcontaminants, fuel . . . ). For example, the presence and amount ofwater in the fluid 106 will generate a characteristic alteration in acyclic voltammetry curve and dialectric reading of the sensor elements104. Similarly, presence and amount of water also exhibit acharacteristic alteration in amplitude of the FTIR spectrum plot 112 ata particular wavenumber. For example, the presence of H₂O in a samplewill exhibit a peak at wavenumbers 3450-3330 cm⁻¹ and carbonyl compounds(e.g. oxidized compounds) will exhibit a peak at wavenumbers 1755-1695cm⁻¹. Such parameters can be sensed in situ by the sensor 102 viautilizing the sensor elements 104. The multiple sensor elements 104,which can include a dielectric sensor, TAN sensor, electro-chemicalsensor, etc. can detect particular chemicals that exhibit a change inthe FTIR spectrum. For example, the I-V (current-voltage) curvegenerated by performing cyclic-voltammetry with an electro-chemicalsensor element exhibits unique characteristics for water and othercontaminants. These same chemicals exhibit a characteristic pattern inthe FTIR plot. As FTIR spectrum information is embedded (or encoded) insensor readings of the sensor elements 104, the FTIR spectrum plot 112can be obtained via employing the sensor filter/fusion component 108.

For example, artificial neural networks have been demonstrated aseffective algorithms for extracting encoded information from one dataseries and synthesizing a new, derived series originally embedded in theoriginal data series. Artificial neural networks can be used byproviding multiple sensor readings from the sensor elements 104 to apre-processing function. The pre-processing function can perform anyneeded scaling, filtering, signal processing, and computations tocombine or calculate additional parameters. An array of values from thepre-processing function (resulting from a manipulation of sensorreadings from the sensor element 104) can be provided as input to theartificial neural network. The neural network can be a wide range ofestablished neural net architectures. An exemplary network is afeed-forward neural network with back-propagation training. Thefeed-forward network is previously trained with a suite of dataexemplars comprised of readings from the sensor elements 104 andcorresponding FTIR spectrum data values. These training values areextracted from a range of fluids including good fluid, degraded fluid,and contaminated fluid such as will be expected to be experienced duringsensor operation. Other well-known systems and/or methods may be used tosynthesize the FTIR spectrum, such as algorithmic methods employingcurve fitting, expert systems, stochastic models, fuzzy logic, datafusion engines, Bayesian belief networks, and support vector machines.

An important characteristic of the sensor 102 comprising a plurality ofsensing elements 104 is that several of the individual sensor elements104 are not merely passive devices providing a specific sampledelectrical value. Rather, the sensor elements 104 can be activelystimulated in a manner that will provide for a more accurate and abroader range of information regarding condition of the fluid 106 andcontaminants present within the fluid 106. For example, disparatestimulus frequencies and amplitudes can indicate different fluidproperties and contaminants.

For example, electrochemical sensor electrodes can be provided witheither a triangular wave or sinusoidal waveform of a particular voltagevalue and frequency. The voltage value and frequency applied to theelectrochemical sensor will indicate the presence of particularcompounds, additives, and contaminants such as water. Spanningparticular voltage ranges and frequencies will cause certain compoundsto oxidize and reduce thereby providing an indication in the IV(current-voltage) curve of the presence of these different chemicals.The selection of voltage and frequency ranges can be dynamicallyadjusted to focus in on compounds of interest or to provide a morecomplete FTIR spectrum to be synthesized. For example, existence of aparticular compound of interested can be indicated on a general widevoltage sweep IV curve. Based on the interpreted IV curve, the cyclicvoltammetry process can then be repeated with within a very limitedvoltage range and at a slower frequency to highlight specificcontaminants detected. This more precise information can be used todynamically increase the accuracy and resolution of the synthesized FTIRspectrum as needed.

Similarly, a conductivity sensor element can also be stimulated duringoperation. Different stimulus frequencies used to activate theconductivity sensor can indicate different fluid properties. Forinstance, the conductivity sensor element can be stimulated with a 2 kHzsine wave. The resultant signal will indicate a degree of fluidconductivity. A higher frequency stimulus can indicate water presence,and a still higher frequency can indicate fluid capacitance. Disparatefluid properties determined are related to the specific compoundspresent in the fluid and are reflected in the FTIR spectrum. Othersensor stimulus signals can be dynamically changed or prescribed in realtime based on previous sensor responses to provide for a very accurateand robust FTIR spectrum. New compounds that appear in the synthesizedFTIR spectrum can be further investigated with targeted,compound-specific stimulus defined for multiple sensor elements (e.g.TAN, Electrochemical, dielectric, MEMs viscosity, . . . ). The broadrange of fluid parameters obtained at various prescribed voltages andfrequencies can be combined using sensor fusion and synthesis techniquesto generate a synthetic FTIR spectrum. After the FTIR spectrum plot 112is synthesized from parameters sensed by the sensor elements 104, thespectrum plot 112 can be analyzed by established analytical methods. Asignificant body of knowledge exists for interpreting the FTIR spectrumplot, which can be readily applied to interpret the new, synthesizedFTIR spectrum plot. In a similar manner, since the sensor elements 104provide information on the chemical composition of the sampled fluid106, lubricity information is embedded in readings obtained by thesensor elements 104. For example, lubricity enhancing additives, waterdilution, fuel dilution, and viscosity may be readily detected by sensorelements 104, and such parameters relate to lubricity performance. It ispossible to synthesize lubricity information from values obtained by thesensor elements 104. For example, an artificial neural network asdescribed above may be trained to generate the lubricity value. Otherwell-known methods can be used to synthesize the lubricity informationsuch as algorithmic methods employing curve fitting, expert systems,stochastic models, fuzzy logic, data fusion engines, Bayesian beliefnetworks, and support vector machines.

In particular, the lubricity measurement 110 and information obtainedfrom analysis of the FTIR spectrum plot 112 can be employed to determinefaults or deficiencies in the fluid and automatically alter thechemistry to maintain the fluid 106. For example, operation of a machineand/or alteration of chemical properties of the fluid 106 can beundertaken automatically based at least in part upon the lubricitymeasurement 110 and the FTIR spectrum plot 112.

Turning now to FIG. 2, a system 200 that automatically maintains fluidwithin machinery based at least in part on a lubricity measurementand/or FTIR spectrum plot is illustrated. The system 200 includes asensor 202 that comprises a plurality if sensor elements 204 thatfacilitate measuring particular parameters of a fluid 206. For example,the sensor elements 204 can obtain measurements regarding pH, viscosity,temperature, TAN, conductivity, water content, and various otherphysical and chemical parameters relating to the fluid 206. Furthermore,the sensor elements 204 can include devices fabricated to particularlyobtain data relating to lubricity of the fluid 206 in particularsituations. For instance, two surfaces can be positioned to incidentallymove relative to one another within the fluid 206, thereby causingfriction between the surfaces (e.g., the fluid 206 is provided to reducefriction between the surfaces). An amount of energy provided to thesurfaces and distances that the surfaces traveled with respect to oneanother can be measured and is indicative of lubricity of the fluid 206.A sensor filter/fusion component 208 can receive parameters sensed bythe sensor elements 204, and can manipulate such parameters to determinea lubricity measurement 210. The sensor filter/fusion component 208 can,for example, comprise various algorithms that include a first-orderchemical model and pattern-recognition algorithms to correlate sensorreadings from the sensor elements 204 with laboratory lubricitymeasurements. Furthermore, as FTIR spectrum information is embedded inreadings obtained by the sensor elements 204, the sensor filter/fusioncomponent 208 can facilitate generation of a FTIR spectrum plot 212. Thespectrum plot 212 can thereafter be analyzed via conventional methods.For example, the FTIR spectrum may indicate a strong presence of waterand oxidative compounds.

An analysis/action planning component 213 can be provided in connectionwith a control component 214 to facilitate automatic maintenance of thefluid 206 within machinery. For example, the analysis and actionplanning component 213 can establish a current usefulness of the fluid206 and identify any deficiencies. The analysis/action planningcomponent 213 will evaluate potential action possible such as injectingnew fluid, an anti-oxidant additive, or a lubricity-enhancing additive.The analysis/action planning component 213 may then prescribe a specificamount of additive to be introduced into the fluid supply. Subsequentanalysis of the lubricity measurements and FTIR spectrum plot generatedwill confirm that the fluid change was made and that the desired changein fluid property was achieved. If necessary, additional fluidadjustments can be made in a dynamic, continuous manner.

After the desired fluid change is defined by the analysis and actionplanning component 213, the control component 214 can facilitateautomatic injection of additional fluid and/or fluid additives from afluid/additive reservoir 216 to the fluid 206. Moreover, the lubricitymeasurement 210 and the FTIR spectrum plot 212 can be employed asfeed-back and/or feed-forward data. The control component 214, forexample, can deliver control commands to the fluid/additive reservoir216 based at least in part upon the lubricity measurement 210 and/or thespectrum plot 212. The fluid/additive reservoir 216 can comprise variousactuators, MEMS valves and/or micro-fluidics that are responsive to thecontrol component 214 (e.g., valves releasing fluid and/or additivesinto machinery can be responsive to control commands from the controlcomponent 214). In accordance with another aspect of the presentinvention, machinery 218 can be controlled by the control component 214based at least in part upon the lubricity measurement 210 and/or theFTIR spectrum plot 212. For example, if the lubricity measurement 210indicates that there is insufficient lubricity for a present and/orfuture operation of the machinery 218, then the control component 214can inform the machinery 218 to halt operations or to operate at a levelwhere a lower level of lubricity will not damage the machinery 218.

Turning now to FIG. 3, a system 300 that facilitates obtaining ameasurement of lubricity within a fluid and/or a spectrum plot of asample of fluid is illustrated. The system 300 includes a casing 302that has aperture(s) 304 to allow fluid 306 to enter the casing 302. Theaperture(s) 304 can be opened to allow fluid to enter the casing 302 andclosed upon the filling of a reservoir 308 within the casing 302. Anactuator 310 is provided to facilitate opening and/or closing theaperture(s) 304. A sensor 312 with a plurality of sensor elements 314 isprovided within the casing, wherein the fluid 306 confined within thereservoir 308 contacts the sensor elements 314. A heating/coolingcomponent 316 is provided to heat and/or cool fluid 306 that is confinedwithin the casing 302. Heating and/or cooling the fluid 306 enables thesensor elements 314 to obtain more robust measurements regarding thefluid 306. The parameters sensed by the sensing elements 314 arereceived by a sensor fusion component 318, which can manipulate the datareceived by the sensor elements 314 to output a lubricity measurement320 and a FTIR spectrum plot 322.

Utilizing the heating/cooling component 316 to vary temperature of thefluid 306 near the sensor elements 314 provides a more complete andaccurate mapping of readings from the sensor elements 314 to thespectrum plot 322. A mapping from discrete sensor readings from thesensor elements 314 is performed within the sensor filter/fusioncomponent 318 via standard non-linear mapping techniques such asartificial neural networks. Such mapping technique has been performed inconventional systems that analyze vibration spectrum data from sampledmotor current data. It is further to be appreciated that the lubricitymeasurement 320 and the FTIR spectrum plot 322 be employed toautomatically maintain the fluid 306. For example, chemical additivescan be automatically added and/or removed from the fluid 306 based atleast in part on the measured lubricity 320 and/or the FTIR spectrumplot 322.

Turning now to FIG. 4, a methodology 400 for determining lubricity offluid within machinery and obtaining a FTIR spectrum plot of fluidwithin machinery is described. While, for purposes of simplicity ofexplanation, the methodology 400 is shown and described as a series ofacts, it is to be understood and appreciated that the present inventionis not limited by the order of acts, as some acts may, in accordancewith the present invention, occur in different orders and/orconcurrently with other acts from that shown and described herein. Forexample, those skilled in the art will understand and appreciate that amethodology could alternatively be represented as a series ofinterrelated states or events, such as in a state diagram. Moreover, notall illustrated acts may be required to implement a methodology inaccordance with the present invention.

At 402, a multi-element sensor is provided within a fluid. Themulti-element sensor can be positioned in machinery in a location thatmonitoring of lubricity is desirable (e.g., bearing raceway, within afuel pump, hydraulic reservoir, gearbox, fuel tank, . . . ). Themulti-element sensor can sense a plurality of physical and chemicalparameters relating to the fluid, including presence of lubricityenhancing additives (e.g., ZDDP and TCP), electrochemistry, TAN,dielectricity, temperature, water, density, viscosity, etc. Furthermore,various other devices that can obtain information indicative oflubricity of the fluid can be provided. For instance, a device withmultiple surfaces can be provided, wherein two or more surfaces areforced to contact one another. Moreover, a device that can determine anability of the fluid to adhere to particular surfaces can be provided.

At 404, the multi-element sensor obtains measurements relating to thefluid (e.g., temperature, density, viscosity, presence of lubricityenhancing additives, ability of the fluid to adhere to particularsurfaces, friction measurements, . . . ). At 406 the measurementsobtained by the multi-element sensor are filtered and/or fused accordingto one or more filtering and/or fusing algorithms. In accordance withone aspect of the present invention, the data from the sensor can befiltered and/or fused with respect to a chemical model and patternrecognition correlating to sensor readings with laboratory lubricitymeasurements. Such a technique ensures that a final lubricitymeasurement correlates to a measurement that is obtained in laboratoryprocedures without associated time-consumption and cost. Moreover, asthe multi-element sensor can continuously monitor the fluid, a robustcontrol of lubricity can be generated.

At 408, a lubricity measurement is obtained based at least in part uponparameters sensed by the multi-element sensor after filtration/fusion.At 410, a FTIR spectrum plot of the fluid is obtained. Creation of theFTIR spectrum plot is possible due to a correlation that exists betweenparameters measured by the multi-element sensor and known FTIR spectrumplots. By utilizing sensor filtering and sensor fusion in act 406together with non-linear sensor mapping, it is possible to construct anFTIR spectrum plot for the particular fluid. The obtained spectrum plotcan thereafter be analyzed according to conventional methods.

Turning now to FIG. 5, a method 500 for automatically controllinglubricity within machinery is illustrated. At 502, a multi-elementsensor that measures a plurality of parameters relating to a fluid isprovided. For instance, the multi-element sensor can obtain measurementsrelated to the fluid physical and chemical properties such astemperature, pH, acidity, water, oxidation levels, etc. Moreover, themulti-element sensor can include friction-sensing elements to facilitatedetermining lubricity of the fluid. At 504 measurements are obtained bythe multi-element sensor. At 506, lubricity of the fluid is determinedat least in part via sensor filtering/fusion techniques. At 508 adetermination is made regarding whether there is sufficient lubricitywithin the fluid. If sufficient lubricity exists, the methodology beginsagain at 502. If not, a prescribed amount of alteration of the fluid isdetermined at 510. For example, a type of additive and an amount of suchadditive to inject into the fluid can be determined.

For a more particular example, information such as the amount of stressor loading the fluid is experiencing can facilitate determination of atype and amount of additive to inject into the fluid. Ahigh-temperature, high-vibration environment can place greater demandson the fluid and require a higher degree of lubricity than typicallyrequired for cool-running low-stress operation. Based on the context andsystem demands, a substantial amount of additive to be introduced in thesystem can be prescribed to provide even greater lubricity and enhancemachinery protection. Furthermore, based at least in part uponanticipated future loading and prognostics of expected machinery demandsand predicted rate of fluid degradation, additives can be introducedprior to critical fluid parameters (such as lubricity) reaching anunacceptable level. Information regarding future loading and expecteddegradation rate of fluid can be obtained using established prognosticsmodels such as time-series analysis or artificial neural networks or canbe obtained from operational and mission-planning databases. Employingprognostics and taking preventive action before the fluid reaches acritical level provides even greater capability for prolonging fluidlife and preventing mechanical damage or catastrophic failure. It ispossible that waiting until a parameter value such as lubricity reachesa critical level before initiating control action may make the fluidcondition irreversible.

At 512, the prescribed alteration is effectuated into the fluid (e.g.,lubricating elements are added). For example, a controller can beprovided to constantly receive data relating to lubricity, andautomatically maintain the fluid based at least in part upon thereceived data. The ability to continuously monitor lubricity providesfor an enhanced control system and prevents machinery from beingsubjected to unnecessary friction between moving elements. Thus theability to continuously monitor lubricity and automatically maintainfluid based at least in part on the measurements is a significantimprovement over conventional systems. For example, a conventionalsystem requires extraction of a fluid sample and time-consuminglaboratory test procedures to determine lubricity. While the laboratorytest procedures are being completed, a machine could be subject to adamaging amount of friction, thereby resulting in irreparable harm tomachinery. In contrast, the present invention enables real-time controlof fluid maintenance regarding lubricity of the fluid.

Referring now to FIG. 6, an exemplary micro electro-mechanical systemtype (MEMS-type) multi-element fluid sensor 600 that can be employed inconnection with determining lubricity of a fluid and generating a FTIRspectrum plot is illustrated. The multi-element fluid sensor 600 affordsfor continuous in situ monitoring of a variety of fluid parameters via aplurality of sensing devices (elements). A data filtering/fusionframework (not shown) can be associated with the fluid sensor 600 tofacilitate condensing, combining, evaluating and interpreting thevarious sensed data. The sensor 600 can be employed in rotatingmachinery that utilizes fluid as lubrication. In addition, the sensor600 can also be applied to measure various parameters of hydraulicfluids and cutting fluids, as well as drilling fluids, fuels,refrigerants, food and cosmetic fluids, and biological fluids. Inaccordance with one aspect of the present invention, the sensor 600 canbe placed within machinery where friction between moving parts can beproblematic (e.g., a bearing raceway, fuel pump, valve, . . . ). Thefluid sensor 600 includes a semiconductor base 602 that preferablycomprises silicon, however, any suitable material may be employed.Located on the surface of the base 602 are a plurality of sensingdevices 604 for sensing various parameters of a fluid. Moreparticularly, the sensing devices 604 include a pH or TAN sensor 606 forsensing acidity or basicity of the fluid. A chemical sensor 608 providesfor performing electro-chemical operations (e.g. cyclic voltammetry) forsensing chemistry of the fluid. A conductivity sensor 610 provides forsensing electrical conductivity of the fluid. A temperature sensor 612provides for sensing temperature of the fluid.

The pH/TAN sensor 606 includes a reference electrode 614 comprising anysuitable material (e.g., Ag, AgCl) and a pH/TAN electrode 616 comprisingany suitable material (e.g., palladium-palladium oxide (Pd-PdO)). ThepH/TAN sensor 606 provides for sensing the pH (for aqueous fluids), TAN(total acid number), TBN (total base number), and SAN (strong acidnumber) of a lubricant or fluid being analyzed. An exemplary discussionrelating to pH sensors is found in “A Pd-PdO Film Potentiometric pHSensor”, by Karagounis et al., IEEE Transactions on BiomedicalEngineering, Vol. BME-33, No. 2, February 1986 which is herebyincorporated by reference in its entirety.

The chemical sensor 608 is a b 3-electrode configuration that includes areference electrode 618 comprising any suitable material (e.g., Ag,AgCl), a working electrode 620 (e.g. comprising Ag) and a counterelectrode 622 (e.g., comprising Ag). The chemical sensor 608 is of adesign typically used in conjunction with voltammetric techniques. It isto be appreciated that other suitable sensor designs, including a2-electrode or 4-electrode electro-chemical sensor, may be employed.When either an AC or DC voltammetric signal is applied to the workingelectrode 620, a response current is generated between the workingelectrode 620 and the counter electrode 622. The applied voltammetricsignal can be a symmetric triangular signal, a sinusoidal signal, or anyother suitable waveform. The amplitude and frequency of the signal canvary based on the fluid composition and analysis desired. The responsecurrent signal parameters vary depending upon the electrochemicalprocesses occurring at the surface of the working electrode 620. Theelectrochemical processes are a function of the constituentconcentrations, and the response current is therefore responsive tothese concentrations. The electrochemical sensor is useful fordetermining the presence of contaminants like water or oxidationproduct, for example, in a fluid being analyzed. In accordance with oneparticular aspect of the present invention, the chemical sensor 608utilizes voltammetric techniques to determine presence of particularchemical additives that relate to lubricity of fluid. For instance, thechemical sensor 608 can be employed to determine presence of ZDDP and/orTCP. Moreover, the chemical sensor 608 can be utilized to alter anelectrostatic field to indicate presence of fluids providing enhancedlubricity due to electrostatic field attraction. Alternatively, othersensing elements and/or an independent voltage/current source can beemployed in connection with altering an electrostatic field proximate tothe sensor elements.

The conductivity sensor 610 is of a two-electrode design, however, it isto be appreciated that other configurations (e.g., four electrode) maybe employed. In the preferred embodiment, the two electrodes (624, 626)comprise gold, however, any suitable metal or material may be employed.Two and four electrode conductivity sensors are well known and thusfurther discussion related thereto is omitted for sake of brevity.Knowledge of the conductivity is also useful for determining if metalwear and/or water is contaminating a fluid, for example.

The temperature sensor 612 provides for determining the temperature ofthe fluid being analyzed, and is preferably formed from platinum,however, it is to be appreciated that any material (e.g., gold) suitablefor carrying out the present invention may be employed. The temperaturesensor 612 is patterned on the base 602 in accordance with apredetermined length, width and surface area. Therefore, by knowing thesurface area of the temperature detector 612 and the material of whichit is made, a temperature of a fluid to which the temperature sensor 612is exposed may be determined based on the electrical conductivity of thetemperature detector 612. Knowledge of fluid temperature is useful ininterpreting the health state of the fluid being analyzed becausecertain fluid parameters (e.g. viscosity) are a function of fluidtemperature. Furthermore, the rate of fluid breakdown or additivedepletion is also a function of temperature. Therefore, temperature canbe utilized in connection with determining lubricity of a fluid withinmachinery. It is possible using the temperature sensor element 612 or aseparate element of a similar to design to heat the fluid in thevicinity of the electrodes. The temperature sensor metalization canfunction as a resistance heater. The ability to sense the temperature inthe vicinity of the heater provides the capability for closed-looptemperature control. The ability to operate the various sensor elementsunder specific, controlled temperatures is extremely useful in obtainingmore accurate and robust data readings and in analyzing the sensorreading results.

Each fluid parameter sensor (e.g. pH/TAN sensor 606, electrochemicalsensor 608, conductivity sensor 610, temperature sensor 612) hasrespective sets of contact pads 628-644 that provide for easy couplingto the respective sensors. The fluid sensor 600 is small having a squarearea of approximately 4 mm. Accordingly, the fluid sensor 600 isdesirable for use in applications where space, weight, and power are ata premium but where accuracy, reliability, and sensitivity of measureddata are also at a premium. Furthermore, because the fluid sensor 600 isfabricated in accordance with integrated circuit-like fabricationtechniques, large batches of the fluid sensors 600 may be easily andefficiently produced with good production yields, using conventionalwafer fabrication facilities. For example, hundreds of sensors can befabricated on a standard 4-inch wafer using conventional fabricationmethods and facilities.

Furthermore, it is to be understood that some sensing devices 604 may beomitted from the fluid sensor 600 and/or different types of sensingdevices (e.g., pressure sensor, IR sensor, light sensor, density sensor,light transmission sensor, accelerometer, shear sensor) may beincorporated into the fluid sensor 600. One, some or all of the sensingdevices 604 may be replicated “n” number of times (wherein “n” is aninteger) on a single fluid sensor 600. Such an embodiment may providefor increased reliability because if one particular sensing devicefailed there would be like sensing devices serving as backups. Multiplesensing devices of the same type on a single fluid sensor 600 may alsoafford for increased accuracy as a result of improved signal to noiseratio. The multiple versions of the same sensing element type may span awide range of sizes, ratios, etc., each of which has a range of optimalsensing accuracy. Together these sensor elements 604 provide forsubstantial accuracy over a wide range of parameter values. Thereplicated sensing devices 604 may also improve dynamic range of thefluid sensor 600 as well as versatility (e.g., the fluid sensor 600 maybe employed on a wide range of materials and/or fluids). Such anembodiment may also have enhanced integrity because it may be able tosense if a particular sensing device 604 has failed or to identify thetype of contaminant (e.g., engine coolant, transmission fluid).

FIG. 7 illustrates another exemplary multi-element sensor 700 that canbe utilized in connection with obtaining a measurement of lubricityand/or an FTIR spectrum plot relating to a fluid. The multi-elementsensor 700 includes a pH/TAN sensor 702, an electrochemical sensor 704,a conductivity sensor 706, a temperature sensor 708, and a viscositysensor 710. The pH sensor 702, the electrochemical sensor 704, theconductivity sensor 706, and the temperature sensor 708 are essentiallythe same as that described in connection with FIG. 6 and thereforefurther discussion related thereto is omitted for sake of brevity. Theviscosity sensor 710 provides for sensing the viscosity of a fluid beinganalyzed. In short, the viscosity sensor 710 works in conjunction withthe temperature sensor 708 to facilitate analyzing viscosity of thefluid being analyzed.

The viscosity sensor 710 includes a plurality (e.g., array) offinger-like elements (e.g., cilia) 712 which are plated with anelectrically conductive material. The finger-like elements 712 extendperpendicularly from a surface 714 of the sensor, and the sensor 710functions based on a phenomena that a dissipative or damping force thatresists the motion of the energized finger-like elements 712 results inan increased power demand to maintain oscillation of the finger-likeelements 712 at a particular frequency. A fluid of high viscosity willexert a greater damping force on the oscillating finger-like elements712 than a fluid of lower viscosity. As a result, more power is requiredto maintain oscillation of the finger-like elements 712 at a particularfrequency in a high viscosity fluid than a fluid of lower viscosity.Thus, the viscosity of a fluid may be determined via the micro viscositysensor 710 of the present invention by monitoring the power required tooscillate the finger-like elements 712 at a particular frequency and/orrange of frequencies. Since the viscosity of a fluid is typically afunction of fluid temperature (e.g., typically, the higher the fluidtemperature the lower the fluid viscosity), the present invention alsoemploys the temperature detector 708 to correlate the temperature of thelubricant or fluid with the aforementioned power requirements toaccurately interpret lubricant or fluid viscosity. A more detaileddiscussion relating to the operation and fabrication of such a viscositysensor is found in U.S. Pat. No. 6,023,961, entitled MICRO-VISCOSITYSENSOR AND LUBRICATION ANALYSIS SYSTEM EMPLOYING THE SAME, which asmentioned above is hereby incorporated by reference in its entirety.

FIG. 8 illustrates another exemplary multi-element sensor 800 that canbe employed in connection with the present invention. The multi-elementsensor 800 also includes a processor 802 integrated on a semiconductorsurface 804. The processor 802 can receive measurements obtained by aplurality of sensing elements, such as a pH/TAN sensor 806, anelectrochemical sensor 808, a conductivity sensor 810, a temperaturesensor 812, and a viscosity sensor 814. The processor 802 is employed tocarry out general operations of the multi-element sensor 800 includingdata fusion in accordance with an exemplary data fusion frameworkdescribed in U.S. Pat. No. 6,286,363 entitled INTEGRATED MULTI-ELEMENTLUBRICATION SENSOR AND HEALTH LUBRICANT ASSESSMENT SYSTEM. The processor802 can be any of a plurality of suitable processors, such as forexample: CPU die or processor/logic/storage bonded (flip chip) to thesensor substrate—the sensor elements may be wire bonded to processor I/Oconnection points. The manner in which the processor 802 can beprogrammed to carry out the functions relating to the present inventionwill be readily apparent to those having ordinary skill in the art basedon the description provided herein and thus further discussion relatedthereto is omitted for sake of brevity. Thus, the multi-element sensor800 provides for a substantially autonomous fluid measurement, analysis,and automatic maintenance system. The multi-element sensor 800 canprovide for performing fluid analysis functions as well as affording forself-diagnosis. The multi-element sensor 800 may also be able to verifythat it is in a feasible operating regime.

Turning now to FIG. 9, an exemplary sensing element 900 for obtaining ameasurement relating to lubricity of a fluid is illustrated. The sensingelement comprises a piezoelectric actuator beam 902 with a contactsurface 904 attached to an end of the beam. While the contact surface904 is illustrated as a sphere, it is to be understood that shape of thecontact surface 904 is arbitrary, and any suitably shaped contactsurface can be employed. In particular, different tip geometries (e.g.round tip, planar tip, grooved tip) will result in different measurementvalues and indicate different fluid properties. A voltage source 906 canactuate the beam 902, producing a force F1 towards a wear surface 908.The wear surface 908 is associated with an actuator 910 to move the wearsurface 908 perpendicularly to the beam 902 (e.g., a force F2 isgenerated perpendicular to force F1). While forces F1 and F2 areillustrated as being perpendicular to one another, the direction offorces is arbitrary. All that is required is that the contact surface904 is contacting the wear surface 908 and the contact surface 904 andwear surface 908 are moving laterally relative to one another to providefriction. The sensing element 900 resides within the fluid, thusenabling fluid to lubricate between the contact surface 904 and the wearsurface 908. A measurement relating to lubricity is obtained viamonitoring forces required to move the contact surface 904 over aparticular distance along the wear surface 908 for a given surfacecontact pressure established by force F1. For example, an application offorces F1 and F2 in a positive direction will result in movement of aparticular distance of the contact surface 904 relative to the wearsurface 908. Such measurements can be relayed to a data filtering/fusionnetwork (along with various other measurements relating to lubricity ofa fluid) to obtain a robust measurement of lubricity of the fluid.

Now referring to FIG. 10, an exemplary sensor element 1000 that can beemployed in connection with the present invention is illustrated. Thesensing element 1000 includes a piezoelectric actuator beam 1002 that isconnected to a contact surface 1004. The contact surface 1004 can bemovable in a y-direction with a force F1 via connecting the actuatorbeam 1004 to a voltage source 1006. A wear surface 1008 driven can alsobe movable in the y-direction via a force F2 provided by an actuator1110. The contact surface 1004 can be moved at different distances fromthe wear surface 908. The contact surface 1004 can further be moved inthe vertically-direction in close proximity to the wear surface 1008.The actuator 1010 for the wear surface 1008 exerts the force F2 on thewear surface 1008. As the contact surface 1004 moves vertically (e.g.,in either positively or negatively in the y-direction) near the wearsurface 1008 it will exert a moving force through lubricating film tocause the wear surface 1008 to also move vertically. A sensor andcontroller (not shown) connected to the actuator 1010 can be readilydeveloped to prevent the wear surface 1008 from moving. An amount offorce required to keep the wear surface 1008 stationary is substantiallysimilar to a fluid-transmitted force between the two surfaces 1004 and1008. The control energy required provides an indication of thelubricity of the fluid. Such measurements can be relayed to a datafiltering/fusion network (along with various other measurements relatingto lubricity of a fluid) to obtain a robust measurement of lubricity ofthe fluid.

Turning now to FIG. 11, another exemplary sensing element 1100 thatfacilitates attainment of data relevant to lubricity of a fluid isillustrated. The sensing element 1100 operates in a substantiallysimilar manner as the sensing element 900 illustrated in FIG. 9. Thesensing element includes two surfaces 1102 and 1104 that are positionedat the end of beams 1106 and 1108, respectively. Actuators 1110 and 1112can be provided to press the two surfaces 1102 and 1104 together viadriving the beams 1106 and 1108 towards one another. A voltage source1114 provides controlled power to the actuators 1110 and 1112,respectively. In an alternative embodiment, actuators 1110 and 1112 arenot necessary as the beams 1106 and 1108 are themselves piezoelectricactuators that can be deformed upon application of a voltage from thevoltage source 1114. The surfaces 1102 and 1104 are thereafter movedwith respect to one another to obtain an indication of lubricity offluid that resides between the surfaces 1102 and 1104. For instance, theactuator 1110 can provide a force to the beam 1106 in a positivex-direction and a positive y-direction, while the actuator 1112 providesa force in the negative x-direction to ensure the surfaces are incontact. As the surfaces 1102 and 1104 are frictionally moved relativeto one another, the force required for such movement indicates lubricityof the fluid. The force-distance data can be relayed to a sensorfiltering/fusion component (not shown) to facilitate determination oflubricity within the fluid. Alternatively the surfaces 1102 and 1104 canbe indexed to be proximate to one another and then moved laterally inopposite directions. The force required for movement indicates lubricityof the fluid. In accordance with another aspect of the presentinvention, the surfaces 1102 and 1104 can be indexed to be proximate toone another and thereafter moved away from each other. A force requiredto separate the surfaces 1102 and 1104 can indicate a measure of“stickiness” of the fluid (e.g., “stickiness is indicative oflubricity).

Now referring to FIG. 12, an exemplary sensing element 1200 thatfacilitates attainment of a parameter relating to lubricity of a fluidin machinery is illustrated. The sensing element 1200 includes aplurality of finger-like elements 1202-1212 conventionally utilized tomeasure viscosity, wherein several of the finger-like elements 1202-1212are disparately spaced. As described infra, a measurement of viscositycan be obtained via providing a sufficient amount of power to vibratethe finger-like elements 1202-1214, and thereafter relaying requiredpower and particular frequency to a data fusion network. The finger-likeelements, however, can further be employed to obtain data relating tolubricity via decreasing power to the finger-like elements 1202-1214 anddetermining an ability of the lubrication to adhere to the surface ofthe finger-like elements 1202-1214. For instance, an ability of fluid toadhere to surfaces of finger-like elements 1202 and 1204, which areseparated by a distance of D1, can be compared to an ability of thefluid to adhere to surfaces of elements 1210 and 1212, which areseparated by a greater distance D3. Such measurements are related tolubricity of the fluid. Furthermore, multiple viscosity sensors (eachcomprising a plurality of finger-like elements) can be utilized, whereineach viscosity sensor has disparate spacing between finger-likeelements. Such an embodiment can be beneficial in that fabrication ofthe viscosity sensors can be more efficient, as disparate spacing offinger-like elements is not required for a single viscosity sensor.

In accordance with another aspect of the present invention, thefinger-like elements 1202-1214 can each be coated with a disparatesurface finish. Power can be provided to vibrate the finger-likeelements 1202 at a particular frequency, and thereafter the power can beslowly removed. An ability of fluid to adhere to particular surfacefinishes of the finger-like elements 1202-1212 is indicative oflubricity of the fluid. Measurements relating to an ability to adhere tosurfaces of the finger-like elements can be relayed to a datafiltering/fusion network in connection with providing a measurement oflubricity of the fluid. Information obtained from a separate MEMsviscosity sensing element (not shown) can further increase accuracy ofthe derived lubricity value. It is also possible to vibrate thefinger-like elements 1202-1212 at a varying sinusoidal frequency.Sweeping a wide frequency range and monitoring displacement of thefinger-like elements 1202-1204 can provide a more accurate measure oflubricity.

Now turning to FIG. 13, an exemplary sensing element 1300 employed toobtain data relevant to lubricity of a fluid is illustrated. The element1300 includes a piezoelectric beam 1302 connected to a contact surface1304. The piezoelectric beam 1302 is operatively coupled to a voltagesource/sensor 1305 that delivers voltages to the piezoelectric beam1302, thereby distorting the beam 1302 and forcing the contact surface1304 to contact a wear surface 1306. Moreover, application of a voltageto the beam 1302 can cause a force resulting friction between thecontact surface 1304 and the wear surface 1306 (e.g., the contactsurface 1304 and the wear surface 1308 move relative to one another inthe y-z plane). The wear surface 1306 is coated with an insulating layer1308, and is operably coupled to an actuator 1310 that facilitatesgenerating friction between the contact surface 1304 and the wearsurface 1306. As the wear surface 1306 and the contact surface 1304 moveacross one another, the insulating layer 1308 will wear. Existence of aconductive path, as well as amount of conductivity, is relevant tolubricity of fluid between the contact surface 1304 and the wear surface1306. Such data can thereafter be received by a data filtering/fusionnetwork, which can employ the data in connection with determining anamount of lubricity in the fluid.

In an alternative embodiment, rather than an insulating layer the wearsurface 1306 can include a relatively thick material 1308 that wearsreadily. A displacement measure of the wear surface can be utilized toobtain a measurement relevant to lubricity of lubricant. By maintaininga constant force between the contact surface 1304 and the wear surface1306 while the surfaces 1304 and 1306 are repeatedly moved in closeproximity to each other, a measurement can be obtained of displacementof the wear surface 1306 due to wear. For example, a capacitive value ofthe material 1308 can be monitored to determine an amount of wear. Suchamount of wear can be utilized in connection with obtaining ameasurement of lubricity. While the above exemplary embodiments employpiezoelectric material and various actuators, it is to be understoodthat any method of creating friction between two surfaces iscontemplated and intended to fall within the scope of thehereto-appended claims.

Now regarding FIG. 14, an exemplary sensing element 1400 employed toobtain data relevant to lubricity of a fluid is illustrated. The element1400 comprises a rotating MEMs disk 1402 that tangentially contacts awear surface 1404. An actuator 1406 rotates the MEMs disk 1402 andprovides a force to the wear surface 1404 requiring the disk 1402 andthe wear surface 1404 to contact on another. Forces utilized to rotatethe disk 1402 and to force the wear surface 1404 to contact the disk canbe monitored together with relative distance traveled between the disk1402 and the wear surface 1404. Amounts of force required to rotate thedisk 1402 a distance D1 given presence of a lubricating fluid isrelevant to lubricity of the fluid. Such measurements can be received bya data filtering/fusion network in connection with generating ameasurement of lubricity. It is further to be understood that a forcerequired to stop the rotating disk can be indicative of lubricity.

In another operation of this device 1400 (and other similar devices),the surface 1404 can be a wear surface constructed of relatively thickmaterial that readily wears or abrades. The displacement of the wearsurface 1404 required to maintain a steady pressure on the rotating disk1402 is a measure of lubricity. Alternatively, a holding force requiredto keep the surface 1404 stationary and not move tangentially to therotating disk 1402 is indicative of lubricity. Such measurements can bereceived by a data filtering/fusion network in connection withgenerating a measurement of lubricity.

Now referring to FIGS. 15-21, a plurality of exemplary devices that canbe employed in connection with measuring lubricity of a fluid areillustrated. Turning first to FIG. 15, a sensing element 1500 thatincludes a rotary MEMs disk 1502 is displayed. The disk 1502 is operablycoupled to an actuator 1504 that effectuates rotating the disk 1502, andcan further provide moving the disk 1502 in an x-direction, y-direction,z-direction, or any suitable combination thereof. The disk 1502 can bepositioned proximate to a wear surface 1506, wherein the wear surface1506 is fabricated to provide a substantially match shape with the disk(e.g., the wear surface can be an arc with radius similar to the radiusof the disk 1502). The wear surface 1506 is movable in any suitabledirection, and can be positioned proximate to the rotating disk via theactuator 1504 or another actuator (not shown). A force required torotate the disk 1502 a particular distance can be indicative oflubricity of a fluid. Furthermore, a force necessary to stop the disk1502, a force necessary to inhibit movement of the wear surface 1506,and a force required to separate the disk 1502 and the wear surface 1506are related to lubricity of a fluid that resides between the disk 1502and the wear surface 1506. Moreover, as discussed above, the wearsurface 1506 can be provided with an insulation layer and/or a readilywearable surface to facilitate determination of lubricity of a fluid.

Now referring to FIG. 16, a sensing element 1600 includes a rotary MEMsdisk 1602 that is responsive to an actuator 1604. For example, theactuator 1604, can facilitate rotating the disk, as well as moving thedisk in any suitable linear direction. The disk 1602 can be positionedproximate to a cylindrical wear surface 1606 with an axis of rotationparallel to the axis rotation of the disk 1602, wherein the wear surface1606 can also be rotated and moved in any suitable direction via theactuator 1604 (or a disparate actuator). For instance, the wear surface1606 can be rotated about its axis as well as have a force applied tosuch wear surface 1606 to move it along the perimeter of the disk 1602.Forces required to move the disk 1602 and/or the wear surface 1606 aparticular distance and/or rotate at a particular rate, as well asforces required to stop the disk 1602 and/or the wear surface 1606 canbe indicative of lubricity of a fluid.

Turning now to FIG. 17, a similar sensing element 1700 to the sensingelement 1600 (FIG. 16) is displayed. A rotating MEMs disk 1702 driven byan actuator 1704 is positioned proximate to a cylindrical wear surface1706 that is likewise driven by the actuator 1704 (or a disparateactuator). For example, the wear surface 1706 can be rotated about itsaxis and/or have a force F1 applied to facilitate rotation around theaxis of the disk 1702. Axes of rotation of the disk 1702 and the wearsurface 1706 can be substantially perpendicular to one another. Forcesrequired to rotate the disk 1702 and/or the wear surface 1706 aparticular distance, forces required to stop motion of the disk 1702and/or the wear surface 1706, as well as forces necessary to separatethe disk 1702 and the wear surface 1706 can be indicative of lubricityof a fluid.

Now regarding FIG. 18, an exemplary sensing element 1800 that can beemployed in connection with determining lubricity of a fluid isillustrated. The element 1800 comprises two rotary disks 1802 and 1804that have axes or rotation substantially parallel to one another. Thedisks are rotated and/or moved in any suitable direction by an actuator1806. Alternative, each disk can be rotated and/or moved by disparateactuators (not shown). In this exemplary embodiment, edges of the rotarydisks 1802 and 1804 are moved relative to one another. Forces requiredto rotate a particular disk a particular distance, forces required toinhibit movement of one or more disks, and/or forces necessary toseparate the disks 1802 and 1804 can be indicative of lubricity of afluid.

Referring now to FIG. 19, another exemplary sensing element 1900 thatcan facilitate determining lubricity of a fluid is illustrated. Theelement 1900 includes two rotary disks 1902 and 1904 that have axes ofrotation substantially perpendicular to one another. In disks 1902 and1904 can be rotated about their axes, rotated about each other's axes,and/or moved in any suitable linear direction. An actuator 1906 (or aplurality of actuators) can be provided to facilitate such movement ofthe rotating disks 1902 and 1904. In this exemplary embodiment, edges ofthe rotary disks 1902 and 1904 are aligned with one another. Forcesrequired to rotate a particular disk a particular distance, forcesrequired to inhibit movement of one or more disks, and/or forcesnecessary to separate the disks 1902 and 1904 can be indicative oflubricity of a fluid.

Now turning to FIG. 20, an exemplary sensing element 2000 thatfacilitates measuring a degree of lubricity of a fluid is displayed. Theelement 2000 comprises two rotary disks 2002 and 2004 that can berotated and/or moved in any suitable linear direction via an actuator2006 or plurality of actuators. For example, the disk 2004 can berotated about its axis and simultaneously rotated about the axis of thedisk 2002. The actuator 2006 can position the two disks proximate to oneanother, and forces required to rotate a particular disk a particulardistance, forces required to inhibit movement of one or more disks,and/or forces necessary to separate the disks 2002 and 2004 can beindicative of lubricity of a fluid.

Referring now to FIG. 21, another exemplary sensing element 2100 thatcan be employed in connection with measuring a degree of lubricity of afluid is illustrated. The element includes rotary disks 2102 and 2104,wherein faces of the disks 2102 and 2104 are positioned proximate to oneanother. The disks 2102 and 2104 can be rotated and moved in anysuitable linear direction by an actuator 2106 (or a plurality ofactuators). Forces required to rotate a particular disk a particulardistance, forces required to inhibit movement of one or more disks,and/or forces necessary to separate the disks 2002 and 2004 can beindicative of lubricity of a fluid. Moreover, an amount of wear on thefaces of the disks 2102 and 2104 can indicate a degree of lubricity of afluid. In accordance with another aspect of the present invention, oneor more of the faces of the disks 2102 and 2104 can be provided with ainsulating material and/or a thick surface of readily wearable material.A conductive path between the faces and/or measure of capacitance withrespect to one or more of the faces can be measured to indicate a degreeof lubricity of the fluid.

Turning now to FIG. 22, a methodology 2200 for determining the degree oflubricity of a fluid and/or an FTIR spectrum plot of a fluid isillustrated. At 2202, a multi-element sensor is provided within acasing, which can allow a sample of fluid into the casing andconfinement of the sample within the casing. At 2204, fluid is confinedwithin the casing. For example, the casing can comprise a plurality ofapertures that can be opened and closed by actuator(s) and/or MEMsvalves. When the apertures are opened, fluid can enter/exit the casing.Upon filling the casing with fluid, the apertures can be closed, thusconfining the fluid within the casing.

At 2206, temperature of the confined fluid is varied, which provides fora more complete and accurate mapping of readings from sensor elements toa FTIR spectrum. Moreover, alterations in lubricity with respect toalterations in fluid temperature can be monitored and utilized inconnection with automatically maintaining fluid. At 2208, measurementsof various parameters of a fluid are obtained. For example, temperature,pH, TAN, water, viscosity, density, etc. can all be monitored by sensorelements within the casing. At 2210, data from the sensor elements isfiltered and/or fused. In accordance with one aspect of the presentinvention, one or more artificial neural networks are employed inconnection with filtering and/or fusing data obtained by the sensorelements. At 2212, a measurement of lubricity of the fluid is determinedbased at least in part upon measured parameters. At 2214, a FTIRspectrum plot can be generated upon filtering and/or fusion of dataobtained by the sensor elements. The lubricity measurement and FTIRspectrum plot can thereafter be employed in connection withautomatically maintaining the fluid.

At 2216, the fluid is analyzed. For example, measurements obtained bysensing elements, a degree of lubricity of the fluid, and/or the FTIRspectrum plot can be utilized in connection with analyzing the fluid. At2218 a determination is made regarding whether alteration of the fluidis desirable in connection with maintaining the fluid. For instance, anartificial neural network (or other suitable analysis network) can beemployed to determine whether fluid alteration (e.g., chemicalcomposition alteration) is desirable. If no change is desirable, themethodology 2200 can be repeated. If alteration of the fluid isdesirable, at 2220 an amount of alteration is defined (e.g., an analysiscomponent can be employed to determine amount of desirable alteration).At 2222, fluid alteration is effectuated. For instance, a controller caneffectuate alteration of the fluid via relaying control commands to anadditive reservoir. Thereafter the methodology 2200 can be repeated.

Referring now to FIGS. 23 and 24, exemplary FTIR spectrum plots that canbe synthesized via sensor element readings in accordance with an aspectof the present invention is illustrated. The FIGS. 23 and 24 illustratethat particular chemical compounds are indicated by peaks at particularwavenumbers. For example, referring to FIG. 23, the FTIR spectrum plot2300 indicates a peak of carbon dioxide at wavenumbers of approximately2400 and 250 cm⁻¹. Likewise, spectrum plot 2400 (FIG. 24) indicates apeak of sodium carbonate at wavenumbers of approximately 700 and 900cm⁻¹. The present invention facilitates synthesizing a spectrum plot viasensing a plurality of parameters of a fluid.

In order to provide context for the present invention, FIG. 25illustrates an exemplary environment in which the present invention maybe employed. A three-phase AC induction motor 2500 is depicted driving aload 2502 through a shaft coupling 2504. The motor 2500 includes ajunction box 2506 for receiving conductors from power lines via aconduit 2508, which are tied to power supply lines (not shown) of themotor 2500. The motor 2500 is AC powered and operates at an AC powerline frequency of 60 Hz. However, it is appreciated that different linefrequencies (e.g., 50 Hz) may be employed. Coupled to the motor 2500 isa fluid analyzer 2510 which as will be discussed in greater detail belowprovides for receiving and processing data relating to the health offluid employed by the motor 2500.

The fluid analyzer 2510 includes a display 2512 for displaying to anoperator information relating to the health of the fluid. It is to beappreciated that the fluid analyzer 2510 may also perform otherfunctions relating to determining the health of the motor 2500 (e.g.,current signature analysis, vibration analysis, etc.). The fluidanalyzer 2510 further includes an operator input device 2514 in the formof a key pad which enables a user to enter data, information, functioncommands, etc. as is conventional. For example, the user may inputinformation relating to fluid type via the keypad 2514 for subsequenttransmission to a host computer 2516. In addition, the keypad 2514 mayinclude up and down cursor keys for controlling a cursor that may beshown on the display 2512. The fluid analyzer 2510 includes acommunications port 2518 for interfacing the fluid analyzer 2510 withthe fluid sensor 1600 (FIG. 16) and the host computer 2516 via asuitable communications link.

In order to provide context for the present invention, FIG. 25illustrates an exemplary environment in which the present invention maybe employed. A three-phase AC induction motor 2500 is depicted driving aload 2502 through a shaft coupling 2504. The motor 2500 includes ajunction box 2506 for receiving conductors from power lines via aconduit 2508, which are tied to power supply lines (not shown) of themotor 2500. The motor 2500 is AC powered and operates at an AC powerline frequency of 60 Hz. However, it is appreciated that different linefrequencies (e.g., 50 Hz) may be employed. Coupled to the motor 2500 isa fluid analyzer 2510 which as will be discussed in greater detail belowprovides for receiving and processing data relating to the health offluid employed by the motor 2500.

Referring now in to FIG. 26, a schematic representation of the presentinvention is shown according to one particular aspect of the presentinvention, wherein a fluid analyzer 2600 is integrated with thelubrication sensor 2602. However, it will be appreciated from thediscussion herein that the lubrication analyzer 2600 may be locatedremotely from the motor 2500 (FIG. 25). Furthermore, it is to beappreciated that the host computer may serve to carry out substantiallyall of the functions described herein performed by the lubricationanalyzer 2600. It is also to be appreciated that in accordance withanother specific aspect of the present invention, the lubricationanalyzer 2600 (absent certain components) may be integrated onto asemiconductor chip with the lubrication sensor 2602. In accordance withanother specific embodiment, the lubrication analyzer 2600 may becompletely integrated within the motor 2500 (e.g., in an intelligentmotor), a gearbox, pump, filter, drain, or a bearing, for example.

According to an embodiment of the present invention, the lubricationanalyzer 2510 is part of a communication system including a networkbackbone 2520. The network backbone 2520 may be a hardwired datacommunication path made of twisted pair cable, shielded coaxial cable orfiber optic cable, for example, or may be wireless or partially wirelessin nature. Thus, the fluid analyzer 2510 can be provided with a wirelessreceiver/transmitter 2522 for receiving and/or relaying data pertinentto fluid analysis. Information can also be transmitted via the networkbackbone 2520 between the host computer 2516 and the lubricationanalyzer 2510. The communication link preferably adheres to the RS232Cor DeviceNet standard for communicating command and parameterinformation. However, any communication link suitable for carrying outthe present invention may be employed. Note that the sensor,electronics, software, analysis, and communications may be embedded inthe sensor device.

According to an embodiment of the present invention, the lubricationanalyzer 2510 is part of a communication system including a networkbackbone 2520. The network backbone 2520 may be a hardwired datacommunication path made of twisted pair cable, shielded coaxial cable orfiber optic cable, for example, or may be wireless or partially wirelessin nature. Thus, the fluid analyzer 2510 can be provided with a wirelessreceiver/transmitter 2522 for receiving and/or relaying data pertinentto fluid analysis. Information can also be transmitted via the networkbackbone 2520 between the host computer 2516 and the lubricationanalyzer 2510. The communication link preferably adheres to the RS232Cor DeviceNet standard for communicating command and parameterinformation. However, any communication link suitable for carrying outthe present invention may be employed. Note that the sensor,electronics, software, analysis, and communications may be embedded inthe sensor device. A more detailed discussion relating to the analyticrelationship between fluid viscosity and fluid temperature is presentedin co-pending U.S. Pat. No. 6,023,961.

In the preferred embodiment, the lubrication analyzer 2600 includes ahousing that is suitably shielded to protect the lubrication analyzer2600 from whatever environment (e.g., dust, moisture, heat, vibration,lubrication) the motor 2500 is working in. Additionally, the interior ofthe lubrication analyzer 2600 may be suitably insulated with thermalinsulation between the motor and the lubrication analyzer so as toprotect it from heat generated by the motor 2500. The lubrication sensor2602 can include a pH sensor, an electrochemical sensor, a corrosionsensor, a conductivity sensor, a temperature sensor, a viscosity sensor,ferrous contaminant sensor, and any other suitable sensor that can beemployed to measure various parameters of a fluid within a machine. Thefluid sensor 2602 is operatively coupled to a processor 2604 of thelubrication analyzer 2600 via respective analog to digital (A/D)converters 2607 which convert the analog signals output from the fluidsensor 2602 to digital form for processing by the processor 2604.

A memory 2608 operatively coupled to the processor 2604 is also includedin the fluid analyzer 2600 and serves to store program code executed bythe processor 2604 for carrying out operating functions of the fluidanalyzer 2600 as described herein. The memory 2608 also serves as astorage medium for storing information such as nominal fluidtemperature, pH, electrochemistry, viscosity data, etc. The memory 2608may also include machine specific data and acceptable errorbounds/deviation values which may be used to facilitate determining thesuitability of the fluid being analyzed. Furthermore, the memory 2608may be used to store current and historical fluid or fluid parameterdata, and corrective action which may be recommended. The data can betransmitted to a central processor and/or employed to perform time-basedtrending and analysis to determine fluid or fluid health and futurehealth and desirable re-lubrication interval.

The memory 2608 includes read only memory (ROM) and random access memory(RAM). The ROM contains among other code the Basic Input-Output System(BIOS) that controls the basic hardware operations of the fluid analyzer2600. The RAM is the main memory into which the operating system andapplication programs are loaded. The memory 2608 is adapted to store acomplete set of the information to be displayed. According to apreferred embodiment, the memory 2608 has sufficient capacity to storemultiple sets of information, and the processor 2604 could include aprogram for alternating or cycling between various sets of displayinformation. This feature enables a display 2610 to show a variety ofeffects conducive for quickly conveying fluid state information to auser. Power is provided to the processor 2604 and other componentsforming the fluid analyzer 2600 from a power supply 2612.

The fluid analyzer 2600 includes a data communication system whichincludes a data communication port 2614 and communications card (notshown), which is employed to interface the processor 2604 with the hostcomputer 2516 via the network 2520 (FIG. 25). The communication linkpreferably adheres to the RS232C or DeviceNet standard for communicatingcommand and parameter information. However, any communication linksuitable for carrying out the present invention may be employed.

A memory 2608 operatively coupled to the processor 2604 is also includedin the fluid analyzer 2600 and serves to store program code executed bythe processor 2604 for carrying out operating functions of the fluidanalyzer 2600 as described herein. The memory 2608 also serves as astorage medium for storing information, such as nominal fluidtemperature, pH, electrochemistry, viscosity data, etc. The memory 2608may also include machine specific data and acceptable errorbounds/deviation values which may be used to facilitate determining thesuitability of the fluid being analyzed. Furthermore, the memory 2608may be used to store current and historical fluid or fluid parameterdata, and corrective action which may be recommended. The data can betransmitted to a central processor and/or employed to perform time-basedtrending and analysis to determine fluid or fluid health and futurehealth and desirable re-lubrication interval.

The display 2610 is coupled to the processor 2604 via a display drivercircuit 2616 as is conventional. The display 2610 may be a liquidcrystal display (LCD) or the like. In one particular embodiment, thedisplay 2610 is a fine pitch liquid crystal display operated as astandard CGA display. The display 2610 functions to display data orother information relating to the state of the fluid and if desired thestate of the motor 2500 and recommend action (e.g. change lube in 2weeks). For example, the display 2610 may display a set of discretefluid or fluid condition indicia such as, for example, temperature, pH,electrochemistry, viscosity, and normal operation indicia which isdisplayed to the operator and may be transmitted over the network 2520.The display 2610 is capable of displaying both alphanumeric andgraphical characters. Alternatively, the display 2610 may comprise oneor more light emitting diodes (LEDs) (e.g., a tri-state LED displayinggreen, yellow or red colors depending on the health state of the fluid).An operator input device 2615 can be provided to allow an operator tocommunicate with the processor 2604 via the display 2610.

The fluid analyzer 2600 may also include its own RF section 2618connected to the processor 2604. The RF section 2618 includes an RFreceiver 2620 which receives RF transmissions from the host computer2516 for example via an antenna 2622 and demodulates the signal toobtain digital information modulated therein. The RF section 2618 alsoincludes an RF transmitter 2624 for transmitting information via awireless link to the host computer 2516 for example in response to anoperator input. This wireless link may eliminate the cost, noiseproblems and other problems related with the wireline link 2520. The RFsection 2618 also permits multiple fluid analyzers to share informationand to collaborate on multi-sensor data analysis or to collaborate andperform machinery, sub-system, or process diagnostics.

It should be appreciated that the present invention may be used in asystem which does not include the host computer 2516. All processing,including data analyses and fluid or fluid state estimation and healthdetermination could be accomplished by the processor 2604 and theresults transmitted to a PC or a control computer, such as aprogrammable logic controller (PLC) (not shown), or only displayedlocally on the fluid analyzer display screen 2610. Furthermore, only onedata link may be required. According to another embodiment, theprocessor 2604 could be employed to simply trigger a single bit, digitaloutput, which may be used to open a relay and turn the motor 2500 (FIG.25) off or signal an alarm.

The display 2610 is coupled to the processor 2604 via a display drivercircuit 2616 as is conventional. The display 2610 may be a liquidcrystal display (LCD) or the like. In one particular embodiment, thedisplay 2610 is a fine pitch liquid crystal display operated as astandard CGA display. The display 2610 functions to display data orother information relating to the state of the fluid and if desired thestate of the motor 2500 and recommend actions (e.g. change lube in twoweeks). For example, the display 2610 may display a set of discretefluid or fluid condition indicia such as, for example, temperature, pH,electrochemistry, viscosity, and normal operation indicia which isdisplayed to the operator and may be transmitted over the network 2520.The display 2610 is capable of displaying both alphanumeric andgraphical characters. Alternatively, the display 2610 may comprise oneor more light emitting diodes (LEDs) (e.g., a tri-state LED displayinggreen, yellow or red colors depending on the health state of the fluid).An operator input device 2615 can be provided to allow an operator tocommunicate with the processor 2604 via the display 2610.

Once the processor 2604 has processed all of the respective fluid data,the processed data may be sent to the host computer 2516 for subsequentanalysis and trending. The host computer 2516 may then makedeterminations as to the health of the fluid, the health of themachinery, the health of the process, or the health of the sensorelements based on the data received from the fluid analyzer 2600. Theprocessor 2604 may perform data fusion of the various sensed fluid orfluid sensed parameter data to facilitate condensing, combining,evaluating and interpreting the various sensed data. Accordingly, fluidmaintenance and automatic control for fluid alteration (e.g. additiverelease) can be scheduled to correspond with the state of the fluid.Additionally, the processed data can be compiled for trend analysis andforecasting. Since the fluid analyzer 2600 is integrated with the motor2500, the data sampling rate can be substantially high thus providingfor improved highly accurate and up to date data relating to the healthof the fluid. However, as mentioned above, it is to be appreciated thatfluid diagnosis, trend analysis, forecasting, etc. that could beperformed by the host computer 2516 may also be performed directly bythe fluid analyzer 2600.

The fluid analyzer 2600 includes a voltage supply 2626 which isoperatively coupled to the processor 2604 and the fluid sensor 2602 viaa D/A converter 2627. The voltage driver 2626 provides a series ofdesired voltage to the fluid sensor 2602 in order to drive certainsensing devices (e.g., an electrochemical sensor). The fluid analyzercan also comprise a frequency generator 2630 which communicates with theprocessor 2604 via a D/A converter 2631 if a voltage at particularfrequencies or waveforms are required for proper operation of thesensor(s) 2602. The fluid analyzer 2600 may also include an adaptiveprocessor 2628, such as, for example, a neural network and/or an expertsystem, to facilitate analyzing the health state of the fluid.Alternatively, the adaptive processor 2628 may be located in the hostcomputer 2516 if desired. The programming or training of neural networksinvolves supplying the input and corresponding output data of samplescontaining features, similar to those being searched for. The neuralnetwork in turn learns by adjusting weights assigned to each of theneurons. The weights and threshold values of neurons of the neuralnetwork determine the propagation of data through the network and thusprovide a desired output based on a respective set of inputs.

1. A system that facilitates in situ determination of lubricity in afluid, comprising: a multi-element sensor positioned within a machine,the multi-element sensor obtains data regarding a plurality ofparameters of a fluid, the multi-element sensor comprising two surfaces,at least one of the surfaces comprises a layer of material that wearsreadily; a component that measures capacitance resulting from wear ofthe material; and a component that calculates lubricity of the fluidbased at least in part upon the measured parameters.
 2. The system ofclaim 1, the multi-element sensor comprising: a first surface and atleast a second surface with the fluid between the two surfaces, a firstforce is applied to the first surface and a second force is applied tothe second surface causing the first and second surfaces to generate africtional force between the two surfaces transmitted through the fluid;and a component that measures displacement relative to the two surfacesand the force causing the displacement.
 3. The system of claim 2, atleast one of the forces is substantially perpendicular to at least oneother force.
 4. The system of claim 2, at least one of the surfacescomprises a piezoelectric actuator beam.
 5. The system of claim 2,further comprising at least one control component that controls theposition of at least one of the first surface or the second surface. 6.The system of claim 5, further comprising at least one actuator thatmoves the first surface relative to the second surface, the at least onecontrol component measures the force required to maintain the secondsurface fixed relative to the first surface, the force required is thenused to calculate lubricity of the fluid.
 7. The system of claim 1,further comprising a sensor fusion component that generates a FourierInfra Red spectrum plot at least in part from measurements obtained fromthe multi-element sensor.
 8. The system of claim 1, the multi-elementsensor comprising: a rotating disk; a surface that tangentially contactsthe rotating disk; and a component that monitors a force required torotate the disk a particular distance.
 9. The system of claim 1, whereinthe component that calculates the lubricity of the fluid comprises oneor more artificial neural networks.
 10. The system of claim 1, whereinthe component that calculates the lubricity of the fluid comprises atleast one of a support vector machine, an expert system, a Bayesianbelief network, a fuzzy logic algorithm, and a data fusion engine. 11.The system of claim 1, the component automatically adjusts chemicalcomposition of the fluid based at least in part upon the calculatedlubricity.
 12. The system of claim 1, further comprising a controlcomponent that controls operation of a machine based at least in part onthe calculated lubricity.
 13. A method for in situ determination oflubricity in a fluid within machinery, comprising: placing two surfacestogether with fluid between the two surfaces; moving one surface togenerate a frictional force by relative movement between the twosurfaces and the fluid; and calculating the force required to preventthe other surface from moving relatively and using the information forlubricity measurement.
 14. The method of claim 13, further comprising:fusing data relating to forces utilized to generate the frictional forceand relative displacement of the two surfaces with friction force datato determine lubricity in the fluid.
 15. The method of claim 13, thefrictional force is generated by applying at least one force that issubstantially perpendicular to at least one other force.
 16. The methodof claim 13, further comprising passing fluid between the two surfaceswhile the two surfaces are held in a fixed position relative to oneanother.
 17. A system for calculating lubricity of a fluid, comprising:means for exerting a force on at least two surfaces to create a frictionforce between the two surfaces; means for maintaining fluid between thetwo surfaces; means for monitoring the force exerted on the surfaces;and means for calculating the lubricity of the fluid from the forces.18. The system of claim 17, the two surfaces are moved relative to oneanother to create the friction force.